Common Faults and Troubleshooting of LED Display Screens
1. The whole LED display screen is not lit
① Check whether the power supply and signal line are connected;
② Check whether the test card can identify the interface. If the red light of the test card flashes, it is not recognized. Check whether the light board and the test card are on the same power ground, or the light board interface has a short circuit between the signal and the ground, resulting in the inability to identify the interface (intelligent test card)Get more news about LED Display Screens,you can vist our website!
③ Check whether the 74HC245 has a short circuit, and whether the corresponding enable (EN) signal input and output pins on 245 are short-circuited or short-circuited to other lines
Note: Mainly check the power supply and enable (EN) signal
2. When the LED display screen is scanning at a point, the alternate lines are not lit regularly and the display screen overlaps
① Check whether there is a disconnection or a disconnection or a short circuit between the A, B, C, D signal input port and 245
② Check whether there is a disconnection or a disconnection or a short circuit between the A, B, C, D output port corresponding to 245 and 138
③ Check whether there is a short circuit between the A, B, C, D signals or a short circuit between a signal and the ground. Note: Mainly check the ABCD line signals.
3. When the LED display is fully lit, one or several rows are not lit
Check whether the line between 138 and 4953 is open or poorly soldered, or short-circuited.
4. When the LED display is scanning, two or several rows (usually multiples of 2, regularly) are lit at the same time
① Check whether there is a short circuit between the A, B, C, and D signals
② Check whether the 4953 output terminal is short-circuited with other output terminals
5. When the LED display is fully lit, one or more points (irregularly) are not lit
① Find the control pin corresponding to the module to measure whether it is short-circuited with the row
② Replace the module or single lamp
6. When the LED display is fully lit, one or several columns are not lit
① Find the pin that controls the column on the module and test whether it is connected to the output terminal of the driver IC (74HC595/TB62726,,,).
7. The LED display has a single point or a single column highlighted, or the entire row is highlighted and uncontrolled
① Check whether the column is short-circuited with the power ground.
② Check if the line is short-circuited to the positive pole of the power supply.
③ Replace its driver IC
8. The LED display screen displays confusion, but the signal output to the next board is normal
Check if the STB latch output terminal corresponding to 245 is connected to the latch terminal of the driver IC or the signal is short-circuited to other lines.
9. The LED large screen displays confusion and the output is abnormal 1 Check if the clock CLK latch STB signal is short-circuited.
① Check if the clock CLK of 245 has input and output.
② Check if the clock signal is short-circuited to other lines. Note: Mainly check the clock and latch signals
10. The LED display screen displays color loss
① Check if the data terminal of the color of 245 has input and output.
② Check if the data signal of the color is short-circuited to other lines.
③ Check if the cascade data port between the driver ICs of the color is open or short-circuited, or has a cold solder joint.
Note: The voltage detection method can be used to find the problem more easily. Check whether the voltage of the data port is different from the normal one to determine the fault area.